Artificial hollow thread and device for making same



Dec. 27, 1960 DIETZSCH, 5 2,965,925

ARTIFICIAL HOLLOW THREAD AND DEVICE FOR MAKING SAME Filed 001;. 22, 19572 Sheets-Sheet 1 Dec. 27, 1960 g -rzsc 5 2,965,925

ARTIFICIAL HOLLOW THREAD AND DEVICE FOR MAKING SAME Filed Oct. 22, 19572 Sheets-Sheet 2 Unite ARTIFICIAL HOLLOW THREAD AND DEVICE FOR MAKINGSAME Otto Dietzsch, Sr., Hauptstr. 34, Wangen, Bodensee, Germany Theinvention proceeds from an artificial hollow thread; it is the mainobiect of the invention to impart to the hollow thread preferred textilequalities by appro priate shaping of its cross section. Such propertiesare, above all, soft touch, dull appearance and cohesion atcomparatively low titer by weight.

In order to produce a' low titer by weight in previously knownartificial hollow threads, the cross section of the hollow space must belarge in relation to the thickness of the wall of the tube of solidmaterial. However, this causes the thread to lose its cross stiffnessand to become deformed especially under the mechanical stress whenprocessed, in the textile industry, to a band-shaped body ofapproximately elliptical cross section, and the finished textilestructure (pattern) has irregularly distributed, unattractive glossyareas.

The present invention overcomes this disadvantage of previously knownartificial hollow threads in that it comprises a plurality of, hollowchannels (ducts) distributed over the cross section. Such a many-veinedhollow thread possesses the basic excellent qualities of a conventionalhollow thread having only one hollow vein, namely, good heat insulationand low weight titer, and, in addition, at equal ratio of mass to hollowspace in the cross section, a substantially greater cross stiffness thana singleveined hollow thread owing to the inner walls. Moreover, owingto the strong diffusion of light on its inner walls, the many-veinedhollow thread has a natural, dull appearance. This is further increasedby the fact that the thread has an outside cross section which is notround, i.e., a longitudinal profile, especially if the hollow veins arearranged close to the periphery. The shape of the surface and theproperties of the thread depending thereon can be influenced within widelimits by the size and distribution of the hollow veins.

Suitable materials are those which can be deformed from the viscousphase, i.e., solution or melt. The deforming processes to which thisinvention relates are not only spinning processes in the narrow sense ofthe term, but also rope pressing, rope drawing, etc. The material may beof organic or inorganic nature; Glass may, for inst., be usedas'inorganic material. A preferred field in which the invention may beused comprises materials of organic nature, such as cellulose, cellulosecompounds, aldehyde condensation products, albumin and other nitrogencontaining substances, such as casein, gelatin, also synthetic resins onvinyl, acryl or styryl base, especially modern linear polymer resins.According to their nature, these spinning solutions are developed toform shape-retaining thread structures by suitable solidifying media,for inst., precipitating liquids, cooling gas, etc.

The cross section of the threads may or may not be round and mayespecially in one coordinate substantially more extended thanperpendicular thereto causing the threads to be of band-like shape.

The material may contain coloring or other additives States Patent forthe purpose of producing certain optical efiects, such as iridescence,luster, shot effect or the like.

It also lies within the scope of the invention to arrange on the innerwalls of at least one hollow vein of the many-veined hollow threadsubstances which have a therapeutical or hygienic or generallypharmaceutical effect and to use hollow threads thus impregnated forpurposes of clothing or dressing wounds. It is equally possible toprevent or at least to reduce an undesirable absorption of moisture,body fat etc. by introducing a substance of, for inst., fatty characterwhich is substantially not diffused by the material of the thread.

It is further possible to make the gas or air content of the threadsincompressible by microporous, solid substances, such as aluminumhydroxide or silica gel.

As a further development of the invention, the hollow spaces of thehollow threads may be provided with a loose filling of a solid substancewhich renders the threads particularly suitable for certain technicalpurposes, especially with respect to flavor.

It is apparent that dyes or pigments with fluorescent, phosphorescent orother special properties, if required, can be introduced into the hollowspaces of the hollow threads, in order to produce special opticaleffects. Such introduction of dyes, etc. into fibers has, of course,long been known in the art. It also lies within the scope of theinvention to produce a special glazing effect by metalizing the innerwalls. Such inner mirror coatings can be produced according to the knownprocesses of the socalled wet metalizing.

Another possibility consists in covering the inner walls of the hollowspaces with a substance sensitive to light, in order to produce patterns(images) on the fiber or the textile structure formed by the fiber bymeans of photographic processes known per se. By optically sensitivesubstances we mean, for inst., diazo compounds which have the advantagethat their maximum of sensitivity is located in the short-wave portionof the spectrum, and that it is, therefore, not necessary to protectthem rigorously against light as is the case for highly sensitive silversalts. In addition, they may act as dye coupling components as such andthereby produce color patterns, for which printing stencils areotherwise required. 1 The invention further relates to the production ofsuch many-veined, artificial hollow threads and shows methods for theappropriate construction of spinning heads. Spinning of many-veinedhollow threads of viscous, for inst., molten material is substantiallymore 'diflicult, for many reasons, than spinning of a single-vein hollowthread of the conventional type. Owing to the very large free wallareas, the forces of surface tension act very strongly in the liquidmaterial [of which the thread is made]; for the purpose of maintainingthe spaces (in the veins), these forces must be compensated bycorrespondingly strong counterforces, i.e., high gas pressure, in thespaces and must be limited to only brief action in that the material iscaused to solidify quickly. A'nother production difficulty resides inthe fact that the liquid material leaving the nozzle opening must haveuniform energy of flow and uniform energy of surface tension at allpoints of the space of the subsequent partitions, in order that thedistribution of hollow veins in the cross section of the thread remainsas predetermined. The supply of material must, therefore, be regulatedwith great precision.

The spinning head for producing the above-character ized, many-veinedartificial hollow threads fulfills these operational requirements inthat it comprises, for each thread-forming place, a number of smallcapillary tubes of elastic material corersponding to the number of veinsof the thread to be formed, said capillary tubes being anchored in thewall of a common feed chamber at one end and opening convergently intothe nozzle opening at the other end, where they are bundled to spatialcontact against their inner elastic tension. All these differentfeatures of the new type of nozzle serve the same purpose discussedabove: The capillary form ensures a high drop of pressure within thetube and hence a high velocity of discharge of the vein-filling gas atthe nozzle opening, which serves to overcome the forces of surfacetension of the material which is still in its liquid state. Theconvergent arrangement of the small capillary tubes with respect to thenozzle opening produces a certain funnel effect, which ensures that thematerial uniformly penetrates into the intermediate spaces between thesmall tubes and permeates them. The elastic bundling of the small tubesin the nozzle opening forces the tubes into a reciprocally correlatedposition and maintains them in same, said correlated position beingdependent on the external shape of the tube in the contricting area andhence being predeterminable. Preferably, the small tubes are given anon-round cross section at least in said constricting area, in that theyare, for inst, provided with axially running lay-on ribs which, inaddition to the foregoing, will influence, for inst., equalize theconditions of fiow in the intermediate spaces.

It also lies within the scope of the invention to enlarge the nozzleopening in the manner of a funnel and to have it project beyond theclosing plane of the small capillary tubes. This will make the spinningprocess less sensitive to disturbance (disorder), since the front edgesof the tubes are constantly washed with fresh spinning solution andsince there is always suflicient spinning solution to form an outer skinof the thread of the prescribed wall thickness.

Several embodiments of the invention are described below by way of theaccompanying drawing, in which:

Fig. 1 shows a diagrammatic longitudinal section through a spinningliead for producing a many-veined hollow thread according to theinvention,

Fig. 2 shows a cross section taken on the line II--II of Fig. 1,

Fig. 3 is a top view of the nozzle opening in the direction of the arrowIII of Fig. 1,

Fig. 4 is a partial longitudinal section through a spinning headaccording to Fig. 1,

Fig. 5 is a cross section taken on the line VV of Fig. 4,

Fig. 6 is a top view of the nozzle opening (orifice) in the direction ofthe arrow VI of Fig. 1,

Fig. 7 is a top view of the nozzle orifice of another embodiment of aspinning head, similar to Fig. 6,

Fig. 8 is a partial longitudinal section through the front plate ofstill another embodiment of a spinning head, approximately on the scaleof Fig. l, and

Figs. 9 to 11 are cross sections of different embodiments of many-veinedhollow threads according to the present invention on a very muchenlarged scale.

Fig. 1 illustrates a spinning head having only two spinning nozzles--togive a clearer overall picture. The housing comprises two portions 1 and2 screwed together, which enclose the feed chamber 3 for the material tobe spun into a thread and the annular feed chamber 4 for thevein-filling gas. The feed chamber 3 is supplied by way of the centerpassage 6, and the feed chamber 4, by way of the lateral boring 7. Twoplugs 8 corresponding to the number of spinning nozzles-formed bysoldering together a plurality of small capillary tubes 9 are solderedinto the partition between the two feed chambers. The tubes 9, which areonly shown by lines in Fig. l and about the production of which morewill be said later, project into the feed chamber 4 with their shortends, while their full length projects through the feed chamber 3 intotwo nozzle mouthpieces 10, which have been worked or inserted into thehead portion 2 of the housing. The center portion of the nozzlemouthpieces comprises a preferably annular constriction;

they open conically mainly toward the feed chamber 3. The smallcapillary tubes 9 are of somewhat elastic construction and are securedin the plugs 8 in such a manner that they strive somewhat apart.However, when the spinning head is assembled, their free ends arebrought (forced) together in the constrictions 11 in the nozzlemouthpieces 10, where they thus converge against their internal elastictension and crowd together outwardly in the constricting area accordingto Fig. 2. This increases the funnel effect within the conically openingnozzle mouthpiece 10 on the spinning solution penetrating from the feedchamber. Within the area of the constriction 11 the tubes 9 have,preferably on both sides, a conical wall thickening 12, as is shown inFig. 4 by a considerably enlarged partial section. The projectionscausing the constriction 11 and the convex widenings 12 of the capillarytubes may be interrupted in perpiheral direction. This may serve furtherto influence the shape of the ducts of flow for the spinning solution inthe area of constriction. This will further improve the abovementionedfunnel effect and will produce the additional result of spacing the endsof the tubes projecting beyond the constriction 11 in the outlet planeof the spinning head, as can be seen from Fig. 3.

Experience has shown that all nozzle members determining thecross-sectional shape of the spun thread must be dimensioned with greatprecision. For this purpose, the process used is preferably the methodof producing a molded body for the controlled mixing or delivering atleast two fluids with one main and at least one secondary duct, each ofwhich is connected to a source where fluid is stored, and which have apredetermined form with respect to their cross section and theirreciprocally correlated position, by using an auxiliary material whichtemporarily fills the cross section of the duct, wherein the material ofthe body and the auxiliary material are al ternately super-imposed inlayers in controlled, especially symmetrical correlation to the axis ofthe main duct and wherein the materials, prior to applying another layerof the one material to the outer surface of the layer of the othermaterial last applied, are brought into predetermined dependence, forinst, into identical shape with same by tools aligned to the axis of themain duct, es pecially concentrically operating tools, whereby receivingareas are produced for the holder on the respective intermediatestructure, preferably on its front end, by the removal by regions of theauxiliary material, said holder aligning, for inst, centering theintermediate structure with resnect to the axis of the main duct.

In order to produce an extremely precise predetermined outer shape of alayer, its outer surface is preferably first treated with tools in sucha manner that its measurements fall below the predetermined form, theresulting deficiency is measured and another covering layer of thematerial which is to fill up the deficiency to the predetermined form isapplied to the deficient outer surface by means of a process ofapplication, wherein the deficency measured serves as regulating factorfor the thickness of the layer to be applied. This very precisepredetermined outer form of a layer may also be produced by amulti-stage deficiency correction of several partial layers appliedsuccessively.

Said processes are used in the present case for produclng the smallcapillary tubes 9 and the nozzle mouthpieces 10.

As has already been mentioned at the beginning, it is of decisiveimportance for the production of the manyveined hollow thread that thevein-filling gas is injected into the spinning solution at very highspeed, in order constantly to overcome the forces of surface tensionacting in the spinning solution. The high velocity of the gas in thecapillaryduct has the additional advantage of self-purification. As isknown, modern polymeric plastic products (synthetic products) are notchemically uniform substances, but contain, addition to compounds ofhigher molecular weight, compounds with lower molecular Weight andcorrespondingly higher vapor pressure. These volatile components notonly enter the surrounding atmosphere at the nozzle orifice, where theyform the known white smoke streamers, but also difluse, as experiencehas shown, into the filling gas and hence into the capillaries, wherethey may condense to form a coating which constricts the cross section.Experience has shown the threatened obstruction can be prevented by avery high velocity of the gas in the capillaries.

Another advantage of the narrow capillaries consists in that it acts asreducing valve and hence self-regulating (self-dosing) on the throughputof gas.

The high velocity of the gas is produced by a corresponding fall inpressure in the small tubes, which may amount to several atmospheres.When using suitable filling gases, the thermal expansion efiect (due torelease from tension) may be utilized automatically to supercool the gasthat enters the spinning solution and thereby to accelerate thesolidification of the thread from the inside. As is known, such a gas iscarbon dioxide.

The term small capillary tubes is not to be limited to tubes with hollowcylindrical cross section. In the contrary, the invention comprisesevery profile, for inst., an elliptical profile, as diagrammaticallyshown in Fig. 7.

Nor is the invention limited to the fact that the cross section of thenozzle is very largely filled by small tubes in the area of constriction11. Suitable hollow threads are also produced in that only very fewsmall tubes are used, which, owing to their (springy) elasticity, form asingle layer joining the inner periphery of the constriction, as isshown in Fig. 5. The tubes then occupy the position shown in Fig. 6 atthe nozzle orifice. In this case, the tubes 9 need not be puffed upconvexly in the area of constriction 11.

It is also within the scope of the invention to arrange, instead of asingle constriction 11 in the nozzle mouthpiece 10, several suchconstructions in succession in the direction of flow, in order therebyto influence the conditions of flow within the spinning solution ifrequired. The constriction 11 may also be produced by a special, annularinsert body 13, see Fig. 8, which is produced separately and insertedinto the housing portion 10.

Another advantage of the new type of spinning head consists in that itis largely self-centering, so that it may unhesitatingly be taken apartfor cleaning and then be reassembled.

Figs. 9 to 11 show several forms (phases) of the new, many-veined hollowthread with considerably enlarged cross section.

In the embodiment according to Fig. 9, the spinning solution 8 ispermeated with a plurality of veins A, for inst., 15. Such a thread hasan excellent dull efliect.

Figs. 10 and 11 show hollow threads which can be produced by means of aspinning nozzle according to Figs. 5 and 6. The diflerentcross-sectional shape was produced in that the thread according to Fig.10 was spun with less filling gas per unit of quantity of spinningsolution than the thread according to Fig. 11.

In many respects the new thread material has properties which could beproduced in the past only by combining, for inst., twisting, a pluralityof single-vein hollow threads. The (essential)) advantage of the newfiber consists in that it is practically draw-resistant, i.e., thatseparate threads cannot be pulled out, as is the case in a multi-threadstructure. It is, of course, possible to combine the new many-veinedhollow threads to thread bundles prior to further textile treatment.

The invention is obviously not limited to hollow threads, the solid bodyof which consists of a uniform material. The same is true of theconstruction of the spinning head, which may be equipped with muti-stagenozzles. Such multi-stage nozzles make it possible to produce hollowthreads which have around each hollow vein an annular region of specialmaterial diflering from the actual material of the thread. This annularregion may impart to the hollow thread special properties, especially ofa physical kind, for inst., increased ability to absorb water or otheroptical refractive powers.

What is claimed is:

1. Spinning head for producing many-veined hollow threads comprising abody forming a feed chamber for the substance to be spun and providedwith a plurality of nozzle orifices, a plurality of capillary tubescorresponding to the number of veins of the thread to be formed, saidtubes being secured at one end in the wall of a common feed chamber forthe gas filling said thread veins, passing across said feed chamber forsaid sub stance to be spun and passing groupwise through each of saidnozzle orifices, each of said capillary tubes being provided with aconvex widening arranged at the location of said orifices so that afunnel effect is exerted on the spinning substance flowing through thenozzles.

2. Spinning head according to claim 1 wherein the body forming a feedchamber has at the location of each nozzle orifice at least one conicalconstriction.

3. Spinning head according to claim 1 characterized in that the insidediameter of the capillary tubes is so proportioned that the stream ofgas permeating same is given a velocity which overcomes the surfacetension of the spinning substance passing said nozzle orifice andprevents the diffusion of volatile components of said spinning substanceinto said capillary tubes.

4. Spinning head according to claim 2 characterized in that the insidediameter of the capillary tubes is so proportioned that the stream ofgas permeating same is given a velocity which overcomes the surfacetension of the spinning substance passing said nozzle orifice andprevents the ditfusion of volatile components of said spinning substanceinto said capillary tubes.

5. Spinning head for producing many-veined hollow threads comprising abody forming a feed chamber for the substance to be spun and providedwith a plurality of nozzle orifices each provided with at least oneprojection defining a constriction converging conically from said feedchamber, a plurality of capillary tubes corresponding to the number ofveins of the thread to be formed, said tubes being secured at one end inthe wall of a common feed chamber for the gas filling said thread veins,passing across said feed chamber for said substance to be spun andpassing groupwise through each of said nozzle orifices, each of saidcapillary tubes being provided with a convex widening arranged at thelocation of said nozzle orifices so that a funnnel effect is exerted onthe spinning substance flowing through the nozzles.

6. Spinning head according to claim 5 characterized in that the insidediameter of the capillary tubes is so proportioned that the stream ofgas permeating same is given a velocity which overcomes the surfacetension of the spinning substance passing said nozzle orifice andprevents the dilfusion of volatile components of said spinning substanceinto said capillary tubes.

References Cited in the file of this patent UNITED STATES PATENTS2,360,680 Holzmann Oct. 17, 1944 2,440,761 Sisson et al. May 4, 19482,612,679 Ladisch Oct. 7, 1952 2,674,025 Ladisch Apr. 6, 1954 FOREIGNPATENTS 247,418 Germany May 29, 1912'

